Q: Google Distance Matrix API - Using the service without Google map I wonder if anybody knows whether it is permitted to use a the distance matrix service in the code behind without displaying the google map on that specific web page. The google map will be displayed on another page on the same website, but does using the service elsewhere without the map violate the google terms and conditions?

A: According to the Google Maps API Web Services Documentation:

Use of the Distance Matrix API must relate to the display of information on a Google Map; for example, to determine origin-destination pairs that fall within a specific driving time from one another, before requesting and displaying those destinations on a map. Use of the service in an application that doesn't display a Google map is prohibited.

Looks to me like it's allowed so long as your application eventually displays that information on a Google Map, even if it's on another page.
